MMC3316XMT Datasheet, PDF (10/13 Pages) List of Unclassifed Manufacturers – The MMC3316xMT is a complete 3-axis magnetic sensor with on-chip signal processing and integrated I2C bus.

Eleventh cycle: Master device continues to cycle the
SCL line, and each consecutive byte of data from the
X, Y and Z registers should appear on the SDA line.
The internal memory address pointer automatically
moves to the next byte. The Master device
acknowledges each. Thus:
Eleventh cycle: LSB of X channel.
Twelfth cycle: MSB of X channel.
Sixth cycle: Master device writes to the MEMSIC
device‟s Internal Control 0 register the code [01000000]
as a wake-up call to initiate a RESET action. The
MEMSIC device should send an Acknowledge.**
Seventh cycle: The Master device writes to the
MEMSIC device‟s Internal Control 0 register the code
[00000000] to stop the RESET action. MEMSIC device
should send an Acknowledge.
Thirteenth cycle: LSB of Y channel.
Fourteenth cycle: MSB of Y channel.
A minimum of 50uS wait should be given to MEMSIC
device to finish RESET action before taking a
measurement.
Fifteenth cycle: LSB of Z channel.
Sixteenth cycle: MSB of Z channel.
Eighth cycle: Master device writes to internal MEMSIC
device memory the code “[00000001]” to start a take
measurement.
Master ends communications by NOT sending an
„Acknowledge‟ and also follows with a „STOP‟
command.
Note *: The SET preparation action is only required
when the part is inactive for a long time
(typically >5secends).
EXAMPLE OF SET/RESET
First cycle: A START condition is established by the
Master Device followed by a call to the slave address
[0110xxx] with the eighth bit held low to indicate a
WRITE request. Note: [xxx] is determined by factory
programming and a total of 8 different addresses are
available.
Second cycle: After an acknowledge signal is received
by the master device (The MEMSIC device pulls the
SDA line low during the 9^th SCL pulse), the master
device sends [00000111] as the target address
(Internal Control Register 0). The MEMSIC device
should acknowledge at the end (9^th SCL pulse).
Third cycle: The Master device writes to the MEMSIC
device‟s Internal Control Register the code [00000001]
to prepare for SET action.*
A minimum of 50ms wait should be provided to allow
the MEMSIC device to finish its preparation for the
SET action.*
Forth cycle: The Master device writes to the MEMSIC
device‟s Internal Control 0 register the code [00100000]
as a wake-up call to initiate a SET action. MEMSIC
device should send an Acknowledge.
Note **: The RESET action can be skipped for most of
the applications
USING SET/RESET TO CALIBRATE NULL FIELD
OUTPUT
The integrated SET and RESET functions of the
MMC3316xMT enables the user to remove error
associated with Offset change as a function of
temperature, thereby enabling more precise heading
measurements over a wider temperature than
competitive technologies. The functions effectively flip
the magnetic sensing polarity of the sensing elements
of the device. In its simplest form the procedure and
calculation are:
1) Perform SET/MEASURE (Output1 = H + Offset)
2) Perform RESET/MEASURE (Output2 = -H +
Offset)
3) Calculate H by subtracting the two measurements
and divide by 2
Where H is the applied magnetic field and Offset is the
Null Field output. Time between the Set/Measure and
RESET/Measure operation needs to be kept as short
as possible to minimize error induced by the applied
magnetic field changing between the two operations.
Fifth cycle: The Master device writes to the MEMSIC
device‟s Internal Control 0 register the code [00000000]
to stop the SET action. MEMSIC device should send
an Acknowledge.
A minimum of 50ms wait should be provided to allow
the MEMSIC device to finish its preparation for RESET
action.**
MEMSIC MMC3316xMT Rev.A
Page 10 of 13
8/10/2012